On the Next Beta Patch, GGG is attempting to adjust the Map Drop to improve the number and quality of maps you will receive when completing Maps.
1) Each map boss will have a flat 20% change to drop an additional map. This will not apply multiple times for maps where a map has multiple bosses, nor will it double up when a map boss is twinned.
2) We are making adjustments to the way map levels are decided, that will reduce the odds of low tier maps being dropped.
Together these changes should more than triple the number of +2 maps players would be getting (as well as an improvement of +1 maps), compared to the beta.